In the state of the technique exist numerous tools for the cleaning or physical separation between different liquids that are transported in pipes; another type of tool is oriented to the maintenance and inspection of the internal and external conditions of the hydrocarbon or gas pipelines, that allow to capture and record geometrical information of the pipe, such as size, position and internal and external defects, among others.
Among the inspection tools there are the online inspection tools, which internally travels inside the pipe due to the dynamic of the fluid it transports, owing to this, it is not required to suspend the normal operation of the pipeline to comply with the objective of inspecting the pipe.
The intelligent tools employ different inspection methods. The inspection methods mostly used to detect various aspects of the pipe are: Magnetic flux leakage (MFL) and Ultrasound (UT). The intelligent tools, specially those that employ MFL technology, are the most employed and have been developed in greater number, to the point that there exist a great quantity of patent applications related to tools based on this principle.
Among the documents related with this type of tools it can be found the U.S. Pat. No. 4,153,875, which refers to a testing device through the current for metal tubes that are bended, at least locally. The device operates due to the translational movement of a probe inside the tubes, the probe is equipped with coils that serves as emitter—receptor and with an electrical cable that has connected conductors to the probe and are mechanically coupled to the probe to do the translational movements that continually emerge from the posterior end of the tube and that remains connected to a supply system and exploration of the tube system that are found outside of it. This apparatus has a diversity of modules, where there can be found the one for feed, of detection and the one for storage. However, the described tool on this application does not allow an easy manoeuvrability inside the pipe, given that it doesn't have homokinetic joints and the control of the information received by the sensors is controlled only through an electronic media.
Additionally, it can be found the U.S. Pat. No. 5,864,232 that describes an intelligent tool to analyze anomalies that can be found on the walls of a pipe. This tool presents a cylindrical body that has a feed module, a data storage module, means to generate and transmit a magnetic field; means to read magnetic flux leaks caused by anomalies on such pipe and a plurality of wheels joined to the tools' body, which allow the device to slide through the pipe. Also, the tool on this document present several wheels, only useful for the displacement, and a media to propel the tool through the pipe, which is not recommended, as a much higher energy consumption is had due to the drive module that allows the tool to displace through the pipe.
Moreover, there is the U.S. Pat. No. 6,023,986, which refers to a defects localization system of a pipe that comprises an internal navigation system (INS) and a Global Positioning System (GPS). In particular, this application refers to the method to perform the inspection of the pipe and it does no limits to a sole tool for detection, which leaves an open field regarding the device that can be used inside the pipe. Such tool is too complex and its power consumption is elevated, due to the great quantity of additional modules with which it counts to carry out the defects detection in the pipe. Also, this tool needs specialized personnel to perform the maintenance, operation and interpretation of the data, due to its complexity in operation due to the GPS and INS modules.
In addition, the U.S. Pat. No. 6,100,684 divulges a system to detect cracks and thickness variations on the pipes walls, specially a detection method using such system. This system comprises: media to generate and inject a magnetic flux on a portion of the pipe, media to measure the local magnetic fields on the inside surface of the pipe, media to process, store and localize such measurements, and media for the drive of such system through the fluid flow in the pipe. Such system presents a disadvantage in the area of pipes detection and monitoring, which is based in the inability to turn when deviations or turns are found in the pipe, because when the turn is too close the tool would be wedged there. Also, the system counts with various driving modules that slide and drag the tool.
In addition to the documents mentioned previously, we found the application U.S. Pat. No. 6,640,655 that refers to an intelligent tool that has a driving module, a magnetizing section and a storage and record of data section. Inside the magnetizing section there is a plurality of sensors that detect the different defects that can be presented on the wall of the analyzed pipe. The driving module is in charge of pulling the tool through the pipe. The tool counts with a suspension system that allows determining the thickness of the pipe and thus knowing if deterioration exists.
On the other side, the document nearest in the state of the art to the present invention is the patent application US 2002/0011124, which defines an intelligent tool for the detection of defects that can be found in a pipe, specially to determine the wall thickness of it. This tool is comprised basically by three electronic modules, which are a sensing module, a feed of power module and a data storage module. This tool uses the ultrasound for the detection of defects. The main disadvantage of this tool is that it can only be used for relatively straight pipes, given that its connexion system between modules doesn't allow it to turn easily, which restricts its operation. Also, the described invention on such document doesn't present a plurality of Hall effect sensors nor the cards in charge of them, so it doesn't use a personalized system for groups of sensors and therefore it is not obtained a better information control and a greater precision of the defects that can be presented in a pipe.
The online inspection of pipes present two main problems. The first of these is the obstacles in the pipe as dents, obstructions or geometric restrictions, such as curves or valves that obstruct the displacement of conventional tools, which prevents the coverage of the total length of the pipe. According to the exposed, the tools present inconveniences, given that they don't collect all the data related with these particular sections of the pipe and as a result, the operators obtain an incomplete image or information regarding the state of the pipe. These zones generally can contain potential failures or defects and also, require priority maintenance to ensure the normal operation of the pipe.
Given this, the obtaining of more effective tools to avoid pipe restrictions as the previously mentioned, has been of concern during the last years. Some of these inventions that try to overcome these inconveniences are divulged next.
In this sense we find the U.S. Pat. No. 4,769,598, which refers to an apparatus and method to evaluate in an electromagnetic manner, the walls of the pipe. This invention basically counts with two modules that have some carriers or displacement media that allow the tool to slide through the pipe in an easy and save manner. One of the modules of this tool generates an electromagnetic field that allows the determination of existing defects on the wall of the pipe, that are read by magnetic sensors.
This document presents a disadvantage, which is that in each of the modules comprise at least four rollers or wheels to allow the tool to slide and they only comply that function without allowing such wheels to comply another different function. In addition, the tool described in this document does not count with control and positioning systems, given that it doesn't have multiplexing cards or a control card that supervises the others through an interruption mode sent to the microcontrollers of such cards. Also, given that it doesn't count with these cards, it is not possible to control all the time the received information by the sensors and there's no appropriate communication with the computer for the interpretation of the data by the user.
It exists another problem in the online inspection and is found basically constituted by the interpretation of the information of the obtained data. The way of doing the interpretation of the stored data on the existing tools is the post-inspection interpretation, which leads to the interpretation of the stored data through signal treatment software, through neuronal nets and algorithms that make it a difficult, wasteful and delayed process that normally requires validation and interpretation from an expert. In addition, it must be added that the process requires of high capacity elements and of robust architecture for the storage and processing of the information.
The proposed method on the present invention is the online interpretation, which consists in the analysis of the information taken on the sensing process from the tool and in real time. This way of interpretation offers a robust and versatile tool for all type of users and also, allows the decrease in the number and size of the storage devices that are found on this tool.